Prefeasibility studies sought for Devil’s Gorge scheme on Zambezi river

 The Zambezi River Authority (ZRA) invites expressions of interest by 28 June from qualified consultants to undertake prefeasibility studies for the development of the proposed Devil’s Gorge hydroelectric scheme. In the execution of the services, the consultant will be required to cooperate and liaise with the executing agency the ZRA, which is jointly owned by the Governments of the Republics of Zambia and Zimbabwe and mandated to operate, monitor, and maintain the Kariba dam complex as well as develop the full hydropower potential of the stretch of the Zambezi river (from Kazungula to Kanyemba) that forms a common border between the two states.

The Devil’s Gorge scheme, which is planned to be located at the tail end of the Kariba Dam, downstream of the confluence of the Gwayi and Zambezi rivers, was conceived in 1972 out of a study instituted by the Central African Power Corporation (CAPCO), the predecessor of the ZRA. The aim of the study was to identify possible power sources in terms of which the intergovernmental institution could develop to meet the power demands of Zambia and Zimbabwe. Its recommended scheme included a 181 m-high concrete arch dam, 65 m of which are below the water level of the river, two underground power stations on each side of the river with a total capacity of 1240 MW. The normal retention level of EL 595 was selected, which would impound a reservoir of 33 x 109 m3

In 1992-93, a feasibility study, on the Batoka Gorge Hydroelectric Scheme, was commissioned by the authority during which the Devil’s Gorge Scheme was looked at in greater detail and reserved as one of the potential sites for future development. In addition, the authority requested Tractebel Engineering France (TEF) to undertake an analysis of the Devil’s Gorge project in 2016. No Environmental and Social Impact Assessment (ESIA) has been conducted to date.

The objective of the assignment is to undertake prefeasibility studies that would investigate and recommend an optimal site, around the stretch between approximately 60 km downstream of the proposed Batoka Gorge site and upstream of the area of influence of Lake Kariba. The initially recommended site shall also be analysed and compared with the other alternatives.

The scope of the consulting services, which are scheduled to begin this September and to be implemented over a period of approximately thirty weeks, shall include: (i) Review of all available previous documentation on the Devil’s Gorge project; (ii) Supplement the study’s review with focused and limited field investigations and tests required to firm up the scope of the proposed works, including limited geotechnical investigations; (iii) Identify possible alternative optimal sites for the location of the dam taking into account the findings of the technical, geotechnical, environmental, social and economic considerations. From the long list of alternative sites, two shall be recommended, analysed in detail and ranked based on a multi criteria to be agreed with the client; (iv) Propose an optimal installed capacity, informed by technical, environment, social and economic considerations: (v) Propose an optimal configuration of the scheme considering the bilateral nature of the project; (vi) Prepare a detailed design report describing the scope of the proposed works, and clearly showing the design criteria adopted, assumptions made and the corresponding calculations. Confidential cost estimates of the works as well as an implementation schedule shall also be prepared and included in the report. The draft Terms of Reference for the consulting services can be inspected on the authority’s website at www.zambezira.org.

Source:  Prefeasibility studies sought for Devil’s Gorge scheme on Zambezi river (22/06/2022)